1. Field of the Invention
The present invention relates to a Planar Inverted F Antenna (PIFA) for wireless communication devices such as wireless modems, cellular telephones, personal digital assistants, etc. More particularly, the present invention relates to a radio module and an antenna combined into a single unit.
2. Description of the Related Art
With the rapid progress in wireless communication technology and the ever-increasing emphasis for its expansion, wireless modems on laptop computers and other handheld radio devices will be a common feature. Recently, in the cellular communication industry, there has been an increasing emphasis on internal antennas instead of conventional external wire antennas. The concept of an internal antenna stems from the avoidance of a protruding external radiating element by the integration of the antenna into the device itself. Internal antennas have several advantageous features such as being less prone to external damage, a reduction in overall size of the handset, and easy portability. Among the various choices for internal antennas, a PIFA appears to have great promise. The PIFA is characterized by many distinguishing properties such as relative light weight, ease of adaptation and integration into the device chassis, moderate range of bandwidth, Omni-directional radiation patterns in orthogonal principal planes for vertical polarization, versatility for optimization, and multiple potential approaches for size reduction. The PIFA also finds useful applications in diversity schemes. Its sensitivity to both vertical and horizontal polarization is of immense practical importance in mobile cellular/RF data communication applications because of absence of the fixed antenna orientation as well as the multi-path propagation conditions. All these features render the PIFA to be a good choice as an internal antenna for mobile cellular/RF data communication applications.
One of the most difficult manufacturing and production issues for internal antennas is finding a method for combining the radio module and the antenna in a single unit. One method of combining a radio module and an antenna is by integrating the antenna within a radio module using the same manufacturing processes [xe2x80x9cThe Race for Bluetooth Integration Steams Aheadxe2x80x9d, Wireless Systems Design, October 2000]. A ceramic chip antenna is bonded to the radio chip pads using special assembly techniques. These special assembly techniques make the integral unit expensive and, since the radio chip is small, the antenna performance is not optimal. Furthermore, the radio system designer has no flexibility of tuning the antenna to a particular application and using different radio-chip/antenna combinations because the design of the antenna and the chip is fixed.
A method of integrating a PIFA and a radio module into a single unit is disclosed. The present invention permits the PIFA to be removably secured on the top of a radio module. In one embodiment of the invention, a dielectric antenna carrier is removably mounted on and secured to the radio module. A radiating element or xe2x80x9cpatchxe2x80x9d is then secured to the top of the frame. The patch has feed and shorting pins connected thereto and extending therefrom. The integrated radio/antenna system can be mounted on a PCB using standard surface-mount techniques with the feed and shorting pins soldered to the PCB. In another embodiment of the invention, a cover is removably secured to the carrier to retain the patch on the carrier. The cover has a window formed therein to permit the feed and shorting pins to be soldered to the PCB.
It is therefore a principal object of the invention to provide a single integrated radio/antenna system to reduce the amount of space required on a PCB.
A further object of the invention is to provide a radio/antenna system to reduce the amount of assembly handling and inventory levels in making final wireless communication devices.
Yet another object of the invention is to provide a patch that can be surface-mounted to the PCB.
A further object of the invention is to provide a flexible design of the radio/antenna system to facilitate different radio/antenna combinations.
Still another object of the invention is to provide an integral radio/antenna system that is simply configured, compact, cost-effective to manufacture, and easy to fabricate.
These and other objects will be apparent to those skilled in the art.